A program that makes copies of itself; for example, from one disk drive to another, or by copying itself using
email or another transport mechanism. The worm may do damage and compromise the security of the computer.
It may arrive in the form of a joke program or software of some sort.
Similar to a virus, a worm is a self-replicating program that does not necessarily alter files, but resides
in active memory and duplicates itself. Worms use parts of the operating system that are usually invisible
to the user. It is not uncommon for worms to go unnoticed until their replication eats up system resources,
slowing or stopping other tasks.
The recent MSBlaster worm presented users with a myriad of problems including:
o Error message that svchost.exe (or other software) has generated errors and must be restarted.
o Not being able to copy and paste in various applications
o System instability
o Unusually high network traffic
o Virus software that will not function properly
o Inability to install new software
Additionally, the worm had the ability to launch an attack against windowsupdate.com. If all of the infected computers had tried to repeatedly connect to the site as planned, a denial-of-service would have resulted from all of the traffic (too many computers connecting all at once, resulting in the site becoming inaccessable). Microsoft's update site is NOT at that address, but they had an automatic redirection to the correct page from there. Fortunately, Microsoft found out about the potential attack and took down the windowsupdate.com redirection before the attack was to have started.
If people had been keeping up with their Windows Updates, the Blaster worm would have been a lot less damaging. The security hole that the Blaster worm exploited had a patch available almost 2 months before the worm hit the Internet! (donít† feel bad even Microsoft with all their warnings forgot to update some of† there systemís and yep you guessed it .. they got the blaster worm!)